Sensitive methods to detect carcinogen-DNA adducts are needed to study the mechanism of carcinogenesis as well as a measure of true exposure to carcinogens. Synchronous fluorescence spectroscopy is a more sensitive method compared to conventional luminescence methods. Compared to USERIA (ultrasensitive enzymatic radioimmunoassay), its sensitivity appears to be at the same range, if a large volume of samples can be analyzed. By this method, benzo(a)pyrene- and aflatoxin-DNA adducts were detected not only in various tissues of persons with known exposure to these carcinogens but also in some persons without known exposure. According to the preliminary data, the relationship between the fluorescence intensity and the amount of carcinogen-DNA adducts seems to be in linear correlation.